Development of Solar Cell with World’s Highest Conversion Efficiency by SHARP
Achieving the highest possible solar energy conversion efficiency is at the heart of any solar cell research and development effort, and sharp is no stranger at this. Sharp started the development of its first solar cell back in 1967 by developing a solar cell for space application using single-crystal silicon. Much later on the company began its R&D on triple-junction compound solar cell to further improve efficiency, reduce weight, and increase durability of solar cells which was targeted for space applications. Through this effort in 2003 Sharp achieved 31.5% conversion efficiency. By today’s announcement using the same solar cell structure Sharp at least at the experimental level has achieved a 35.8% conversion efficiency rate.
The common types of solar cells that are in use today are silicon-based solar cell with lower conversion efficiency. Unlike the silicon-based solar cell the compound solar cell comprises of photo absorption layers made from two and more elements such as indium and gallium. Compound solar cells have been utilized in space satellites due to their high conversion efficiency rate. Sharp has increased the efficiency of compound solar cell by improving the regularity of atomic arrangement in each photo-absorption layer namely the top, middle and bottom. In the newly developed solar cell Sharp has been using InGaAs (indium gallium arsenide) for the bottom layer due to its high light utilization efficiency in comparison to the commonly used Ge (germanium) resulting in reduction in wasted current. The development of this new solar cell was part of R&D initiatives which was promoted by Japan’s New Energy and Industrial Technology Development Organization (NEDO).
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